Fundamental errors, no accountability, and forced client remediation
I engaged Forvis Mazars to prepare my 2024/25 tax return, including a CGT calculation they had handled correctly the previous year. The legislation had not changed.
What followed was a complete collapse of basic technical competence, calculation integrity, and professional standards.
One pension contribution was incorrectly grossed up despite the source document being clear.
At the same time, a separate pension arrangement totalling over £14,000 gross was initially omitted entirely.
When queried, I was told contributions should be excluded because “tax relief had already been claimed” — a technically incorrect position for relief-at-source pensions, which was then defended in writing rather than corrected.
These are not minor discrepancies or judgement calls. They are fundamental errors across two entirely separate pension arrangements, combined with incorrect technical reasoning.
I was then explicitly told the team would “ensure the taxable gain matches your figure” — despite never having been provided with my workings or methodology.
That is not calculation. It is outcome-matching.
The CGT computation itself was riddled with unsupported and non-reconciling figures, including unexplained adjustments and arithmetic inconsistencies. No workings, no formulas, no reconciliation, and no audit trail were provided at any stage.
The result was a calculation that was fundamentally non-auditable and unsafe to rely on.
When I raised detailed corrections, no proper recalculation or explanation was provided — yet I was still asked to sign off the return.
At that point, I had no choice but to independently audit and rebuild the entire calculation from first principles.
The engagement failed in its core purpose.
Despite this, there was no meaningful acknowledgement of the technical failures, no ownership of what had gone wrong, and no apology addressing the substance of the issues.
Instead, the firm’s position was that they “rely on client figures”, that the process is “iterative”, and that no compensation was due because no financial loss had yet occurred.
That is not a credible position for a professional firm engaged to prepare a tax return. It is a direct attempt to shift responsibility back onto the client while failing to provide even the most basic means of verifying the work.
Even after disengagement, automated systems continued to issue reminders, disengagement itself required chasing, and responses remained slow, procedural, and consistently avoided the core issues.
In total, their failures forced me to spend over a week auditing and correcting their work, several further days reconstructing the return from first principles, and additional time navigating HMRC systems — all immediately before filing deadlines.
The only resolution offered was to waive their £1,020 fee.
No acknowledgement of technical failure.
No accountability.
No compensation.
🔴 Bottom line
This was not a minor error or a difference of opinion.
It was incorrect technical advice defended in writing, outcome-driven adjustments in place of calculation, non-auditable figures, and a complete breakdown of professional standards.
I would not rely on this firm for tax work under any circumstances.